It is known that it is necessary to wash, disinfect, heat-disinfect, sterilize, dry and possibly package surgical or laboratory instruments or similar, which get soiled during use, so that they can be used again.
To this end, washer machines are used provided with a washing chamber which is accessible from the front, into which support trolleys are inserted for the objects to be washed, so as to carry out the necessary treatment cycle, to then be removed frontally, in the case of machines with a single door, or in a through manner in the case of machines with a double door. The trolleys have a frame which both physically supports the objects or the racks containing the objects, and also acts as a distributor circuit of the washing liquid which, by means of nozzles, impellers or similar delivery members possibly integrated in the frame of each trolley, is directed toward the objects to be treated.
Normally, the washer machines are provided with a circuit to feed the washing liquid, connected to a pump, in order to introduce the washing liquid into the distributor circuit of the trolley loaded inside the washing chamber. In particular, the feed surface faces inside the washing chamber with its delivery or coupling mouth normally connected to the plating which constitutes one of the lateral walls which delimit the washing chamber. The delivery or coupling mouth is associated to a connection bushing provided with a spring which renders it elastically yielding, and is able to be selectively moved axially with respect to the exit direction of the washing liquid, acting against the force of the spring, for a determinate segment, to then assume once again its own original position once the stress has stopped. In mating manner, the trolley has a hydraulic connection member, in a position mating with the connection bushing, for the passage of the washing liquid into the distributor circuit of the trolley. In this way, inserting the trolley into the washing chamber, the hydraulic connection member slides tangentially on the connection bushing which, due to the spring associated with it, yields elastically to allow the positioning of the trolley and, once the hydraulic connection member is aligned in position with the delivery or coupling mouth, the connection bushing itself, elastically thrust on the connection member, determines the desired mechanical and hydraulic connection. This known solution which in substance provides to keep the connection bushings constantly elastically thrust and protruding toward the inside of the washing chamber and to make the connection by means of sliding and contrast of the elastic thrust is described for example in the publication “Steelco: Washer disinfector”, 14 Oct. 2011, pages 30-31.
One disadvantage of this known mechanical solution is that, when the pump is activated, the pressure of the washing liquid has a negative influence on the positioning of the connection bushing, in that, in particular, the elastic thrust of the spring is reduced. Consequently the connection bushing is not stably positioned, it distances itself from the connection member of the trolley and there is a loss or leakage of washing liquid through it, which can also generate unwanted sprays and jets of liquid since the hydraulic seal is no longer guaranteed. This loss determines a drop in pressure in the distributor circuit of the trolley and therefore a reduction in efficiency of the impellers and delivery nozzles of the washing liquid. To compensate this drop in pressure, the pump has to be acted on, with obvious waste of energy. In conclusion, the loss of washing liquid due to the unreliability of the mechanical and hydraulic connection given by the connection bushing and corresponding spring has negative effects on the final quality of the washing, as well as on the running costs of the washer machines in question. Another disadvantage is that, because of the sliding of the connection member on the connection bushing, it is not practically possible to provide packing members, such as O-rings, assembled on the latter, because the direct mechanical action of the trolley would be impeded, or in any case there would be a rapid deterioration of the packing member because of repeated friction.
Document WO-A-2009/016111 describes a hydraulic connection device for a machine for washing objects on a trolley which provides a hydraulic connection pipe protruding from an upper wall of a washing chamber and vertically mobile. This solution is not suitable to make a device for the hydraulic and mechanical connection of the type in question, and is also complex for such purpose, because the latter is installed in correspondence to one side of the washing chamber and the solution known from WO-A-2009/016111 would be excessively bulky if used laterally.
Document DE-A-10627762 also describes a washer machine which comprises an upper hydraulic connector and therefore not suitable to make a device for the hydraulic and mechanical connection of the type in question.
Purpose of the present invention is to obtain a washer machine and a method for the hydraulic and mechanical connection of a trolley carrying objects to be washed to a feed circuit of a washing liquid for a machine for washing objects which guarantees a reliable mechanical and hydraulic connection, preventing the losses of washing liquid and undesired drops in pressure known in the state of the art, and which is compact and not bulky.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.